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(12) United States Patent (10) Patent No.: US 6,469,963 B1 Sawada Et Al

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(12) United States Patent (10) Patent No.: US 6,469,963 B1 Sawada Et Al USOO6469963B1 (12) United States Patent (10) Patent No.: US 6,469,963 B1 Sawada et al. (45) Date of Patent: Oct. 22, 2002 (54) OPTICAL RECORDING MEDIUMAND 5,499.225 A 3/1996 Yoshimura METHOD OF INFORMATION RECORDING/ 5,721.856 A 2/1998 Takeuchi READING AN OPTICAL RECORDING 5,825,726 A 10/1998 Hwang et al. MEDIUM 5.940,853 A * 8/1999 Ooi et al. ................... 235/454 6,021,103 A 2/2000 Tani (75) Inventors: Yasuo Sawada, Tokyo; Toru Yashiro, 6,198.708 B1 * 3/2001 Suzuki ..................... 369/84 X Kanagawa; Eiji Noda, Shizuoka, all of (JP) FOREIGN PATENT DOCUMENTS EP O 552 986 A2 1/1993 (73) Assignee: Ricoh Company, Ltd. (JP) EP O 595 358 A2 10/1993 EP O 704844 A1 9/1995 (*) Notice: Subject to any disclaimer, the term of this EP 0 712 130 A1 11/1995 patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days. OTHER PUBLICATIONS (21) Appl. No.: 09/657,165 Patent Abstracts of Japan, vol. 016, No. 050 (P-1308), Feb. 7, 1992, JP 03 250342 A, Nov. 8, 1991. (22) Filed: Sep. 7, 2000 * cited by examiner Related U.S. Application Data 62) DivisionVision of application No.NO. 09/240,679,of 9, filedIlled on Feb. 2Z, Primary Examiner-Paul W. Huber 1999, now Pat. No. 6,137,769. (74) Attorney, Agent, or Firm-Dickstein Shapiro Morin & (30) Foreign Application Priority Data Oshinsky LLP Feb. 2, 1998 (JP) ... ... 10-020967 (57) ABSTRACT Dec. 17, 1998 (JP) ........................................... 1O-3591.33 An optical recording medium which includes a PMA area, a (51) Int. Cl." .................................................. G11B5/09 TOC area, program area, an area that includes a user area (52) U.S. Cl. ...................................................... 369/47.1 and lead-out area. A portion of the PMA area, which relates (58) Field of Search ........................... 369/3201, 47.55, to the program area, is in a recorded State and the TOC area 369/47.12, 47.13, 53.2, 53.24, 53.37, 53.41, is in an unrecorded state. Alternatively, the PMA may be in 53.45, 84, 275.3 an unrecorded State. In addition, a password may be recorded in a portion of an information area. A method of (56) References Cited erasing the medium and a System for reading and recording information are also provided. U.S. PATENT DOCUMENTS 5,337,357 A 8/1994 Chou et al. 1 Claim, 3 Drawing Sheets START READING CONTROL DATA OF CD-RW MEDIUM RECORDING CONTROL DATA N ANOTHER MADIUM OF EXTERNAL DATA STORAGE UNIT ERASNG CONTROL DATA OF CD-RW MEDUM ERASING LEAD-OUT AREA CD-RW MEDUM END U.S. Patent Oct. 22, 2002 Sheet 1 of 3 US 6,469,963 B1 F.G. 1 F.G. 2 U.S. Patent Oct. 22, 2002 Sheet 2 of 3 US 6,469,963 B1 F.G. 3 - 41 erased PMA - 41 erased TOC area 42 program program area area - 43 - 44 erased lead-out area - 44 FG. 4A FIG. 4B PMA - 41 - 42 program - 43 area for system information lead-out area - 44 FIG. 5 U.S. Patent Oct. 22, 2002 Sheet 3 of 3 US 6,469,963 B1 62 67 CD-R/RW EXTERNAL UNIT DATA STORAGE UNIT DISPLAY DISPLAY CONTROL NPUT DEVICE DEVICE | 63 65 F.G. 6 START READING CONTROL DATA OF CD-RW MEDIUM RECORDNG CONTROL DAA N ANOTHER MADI UM OF EXTERNAL DATA STORAGE UNIT ERASING CONTROL DATA OF CD-RW MEDIUM ERASING LEAD-OUT AREA CD-RW MEDUM F.G. 7 US 6,469,963 B1 1 2 OPTICAL RECORDING MEDUMAND PMA 41, the TOC area 42, and the lead-out area 44, are METHOD OF INFORMATION RECORDING/ erased. The user information recorded in the program area READING AN OPTICAL RECORDING 43 remain intact. However, there are no CD drives available MEDIUM which can read the user information Stored in the program area 43, because there is no control data in the filing This application is a divisional application of application information areas. Ser. No. 09/240,679 filed on Feb. 2, 1999, now U.S. Pat. No. Accordingly, there are currently no methods to read user 6,137,769, which is hereby incorporated by reference. information stored in the program area 43 of a CD-RW medium when the medium is accidentally erased by a BACKGROUND OF THE INVENTION quick-erase method. 1. Field of the Invention SUMMARY OF THE INVENTION The present invention relates to an optical recording medium capable of retaining the Secrecy of Stored informa The present invention has been made in view of the tion and to a method of erasing, recording, and reading the above-discussed problems and an object of the present Stored information while retaining a high level of Secrecy. 15 invention is to address and Solve these and other problems. 2. Discussion of the Background The present invention provides an optical recording Optical recording media are disc-shaped media capable of medium which includes an information area. The informa being read and recorded to by optical devices. For example, tion are is comprised of a data area, in which user informa Compact Discs (hereinafter referred to as CDs) such as a tion can be Stored, and a filing information area, in which Compact Disc Digital Audio (CD-DA), a Compact Disc control data for access to the user information can be stored. Read Only Memory (CD-ROM), a Compact Disc Record Initially, the data area is in a recorded State and the filing able (CD-R), and a Compact Disc ReWritable (CD-RW), or information area is in an unrecorded State. large capacity optical recording media Such as a Digital The optical recording medium may further include a Video Disc Read Only Memory (DVD-ROM), a Digital password that is recorded in a portion of the information Video Disc Recordable (DVD-R), and a Digital Video Disc 25 aca. ReWritable (DVD-RW) are well known. These media have The optical recording medium may be a CD-R or a become wide spread as information recording and transmit CD-RW which includes an information area comprising a ting media. In particular, CD-RW media have become data area and a filing information area. The data area remarkably wide spread as erasable/rewrite-able CD media. includes a program area in which user information is Stored When these optical media are used as information trans and a user area in which information can be Stored. The mitting media, it is often important to keep information filing information area contains control data used in acceSS Stored within the media Secret. For example, data Stored in ing the Stored user information. The filing information area a CD can be easily read by a commercially available CD includes a PMA, a TOC area, and a lead-out area. The user drive or CD player. Therefore, a problem which occurs is area, the TOC area, and the lead-out area are in an unre 35 corded State. Both the program area and a portion of the that Secret information is easily leaked when an optical PMA are in a recorded state. The optical recording medium recording medium used to Store the Secret information is may further include a password that is recorded in a portion read by an unauthorized perSon. of the information area. When the medium is used as an The CD-RW media can be reused by erasing information information recording/reading System having System infor which has been Stored. Information erasing methods for 40 mation that is peculiar to the System, the System information CD-RW include a full-erase method in which all the may be recorded in the medium. In this case, the System recorded data is erased and a quick-erase method in which information is used as a password, and the verification of the only control data is erased. Control data is necessary to password may be done by the information recording/reading allow a CD drive to access the information stored in the data System automatically. Specifically, when the System infor area of a CD-RW. The quick-erase method is used in order 45 mation is recorded in the data area, then control data for to quickly make a CD medium ready for rewriting. access to the System information may be further recorded in FIGS. 4A and 4B are schematic diagrams illustrating the PMA. area-structures of a CD-RW medium before and after infor In another aspect of the present invention, an erase mation is erased by a quick-erase method, respectively. A method for erasing CD-RW media is provided, which prior art erase method is described hereinafter referring to 50 includes the Steps of reading control data Stored in a filing FIGS. 4A and 4.B. information area of a CD-RW medium, recording the control In FIG. 4A, reference numerals 41, 42, 43, and 44 data in another medium, and erasing only the control data in designate a program memory area 41 (hereinafter referred to the filing information area of the CD-RW medium. as a PMA), a table of contents area 42 (hereinafter referred In Still another aspect of the present invention, an infor to as a TOC area), a program area 43, and a lead-out area 44, 55 mation recording/reading System is provided which includes respectively. an optical recording medium which includes a file informa User information is Stored in the program area 43 of the tion area. The file information area includes a PMA which is CD-RW medium shown in FIG.
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